Clutch driven plates generally utilize vibration damping means in a manually-actuated vehicle transmission to overcome objectionable vibration and rattle during the torsional coupling of the engine driven shaft and the transmission input shaft by a friction clutch. A conventional vibration damper assembly includes a hub having an internally splined passage to receive the splined end of a transmission input shaft and a radial flange, a clutch plate journalled on the hub and carrying the friction facings at its periphery, a spring retainer plate journalled on the hub on the opposite side of the hub flange from the clutch plate, and damper springs positioned in axially aligned sets of spring windows in the hub flange and the clutch and spring retainer plates. The clutch plate and spring retainer plate are connected together by stop pins extending through elongated peripheral notches in the hub flange.
This damper assembly provides for a substantially constant rate of energy dissipation, and friction washers may be positioned between the hub flange and the clutch and spring retainer plates to provide additional damping friction in predetermined stages. However, the above described vibration damper assembly has proved to be inadequate where specialized problems occur, such as gear rattle at an idle condition, necessitating a multi-stage vibration damping arrangement, with or without friction damping in the stages. The present invention provides such a multi-stage damper to overcome the specialized problems encountered in a vehicle drive line.